DOJ gets court permission to attack botnet

The DOJ seizes servers and serves search warrants in an effort to take down the long-running Coreflood botnet

By Grant Gross | 13 April 11

The U.S. Department of Justice and U.S. Federal Bureau of Investigation have obtained a temporary restraining order allowing them to disrupt a computer virus that created an international botnet controlling more than 2.3 million computers as of early 2010, the DOJ announced Wednesday.

In an unprecedented move, the temporary restraining order, issued Tuesday, will allow the FBI and the U.S. Marshal for the District of Connecticut to set up servers at the Internet Systems Consortium or other ISPs that would stop infected computers from continuing to spread the Coreflood virus, according to court records.

The order allows the law enforcement agencies to send commands to infected computers that stops the Coreflood virus, the DOJ said.

"Allowing Coreflood to continue running on the infected computers will cause a continuing and substantial injury to the owners and users of the infected computers, exposing them to a loss of privacy and an increased risk of further computer intrusions," wrote Judge Vanessa Byrant of the U.S. District Court for the District of Connecticut.

The DOJ and FBI have also filed a civil lawsuit and delivered criminal seizure warrants in an effort to stop Coreflood and the botnet it has created, the DOJ said.

This week, the DOJ and FBI seized five servers that controlled Coreflood-infected computers, the DOJ said in a press release. The agencies also seized 29 domain names used by the Coreflood botnet to communicate with the servers.

In addition, the U.S. Attorney's Office for the District of Connecticut filed a civil complaint Monday against 13 unnamed defendants, alleging that the defendants engaged in wire fraud, bank fraud and illegal interception of electronic communications. The DOJ also obtained search warrants for computer servers across the country, it said.

"Botnets and the cyber criminals who deploy them jeopardize the economic security of the United States and the dependability of the nation's information infrastructure," Shawn Henry, executive assistant director of the FBI's Criminal, Cyber, Response and Services Branch, said in a statement. "These actions to mitigate the threat posed by the Coreflood botnet are the first of their kind in the United States and reflect our commitment to being creative and proactive in making the Internet more secure."

Coreflood records computer keystrokes and other private communications, the DOJ said. Coreflood steals user names, passwords and other private personal and financial information allegedly used by the defendants for a variety of criminal purposes, including stealing funds from the compromised accounts.

In one case described in court documents, criminals used Coreflood to take over an online banking session and cause the transfer of funds to a foreign account.

Law enforcement officials believe that the Coreflood botnet has been operating for nearly a decade, the DOJ said.

The Connecticut criminal complaint said a Michigan real estate company lost more than US$115,000 to fraudulent wire transfers because of the Coreflood virus. A South Carolina law firm lost more than $78,000, and a North Carolina investment company lost more than $151,000, the complaint said. A defense contractor in Tennessee lost more than $241,000 due to the botnet, the complaint said.

"The full extent of the financial loss caused by the Coreflood Botnet is not known, due in part to the large number of infected computers and the quantity of stolen data," the complaint said.

The DOJ urged computer users to update their security software and scan their computers for viruses.

Grant Gross covers technology and telecom policy in the U.S. government for The IDG News Service. Follow Grant on Twitter at GrantGross. Grant's e-mail address is [email protected]